Folding knives are invaluable tools that are used in many aspects of everyday life, and there are many, many types and styles of folding knives. A “manual” folding knife is a very traditional type of tool in which the blade is manually movable by the user between a closed or stowed position in which the sharp edge of the blade is held safely within the handle, and an open position in which the blade is extended in an operable position. There are innumerable variations on this basic theme.
Automatic folding knifes are nearly as ubiquitous as manual folders. These knives include some type of a mechanism—almost always a spring-driven mechanism—that drives the blade from the closed position toward the open position when the user activates the automatic mechanism, typically by pushing a button or analogous activating mechanism. Generally speaking, in a knife that has an automatic opening mechanism the blade is held in the closed position by a latched trigger mechanism. When closed, the blade is under a constant “pre-load” pressure from a spring mechanism. When the trigger is released, the blade is automatically driven by the spring mechanism into the open position.
Most folding knives, whether manual or automatic, incorporate some kind of a mechanism that holds the blade or working implement in the closed position in which the sharp edge of the blade is held safely within the handle. There are many known mechanisms for retaining blades in the closed position, and there are obvious reasons why such mechanisms are used. Among other reasons, blade-retaining mechanisms prevent unintended opening of the knife and thus promote safety. Many folders also include mechanisms that lock the blade in the open position, primarily as a safety feature. There are many different types of these locks.
Manual and automatic knives have many uses and can be used in many different settings, and that has led to a demand expressed by many knife users for knives that are operable in dual modes, both automatic and manual. There are benefits to be had in knives that have dual modes of operation and there are a few known dual mode knives. For instance, dual mode knives are described in U.S. Pat. Nos. 7,603,778 and 8,046,923; both of those knives require switching mechanisms. Nonetheless, there is a continuing need for improved mechanisms for enabling dual operational modes in a folding knife, manual and automatic.
The present invention comprises a folding knife having mechanisms for facilitating dual operational modes. In a first modality, the knife is opened and closed manually. In a second modality, the knife is fully automatic. A lock mechanism securely locks the blade in the open position when either opening modality is being used. When the blade is in the closed position, the knife may be opened either manually or automatically. To open the blade manually, the user simply rotates the blade from the closed to the open position—the lock automatically locks the blade open when the blade is fully open. To open the blade automatically, the lock mechanism functions as the trigger mechanism; the user slides the lock mechanism to actuate the automatic open mechanism. Again, when the blade is in the fully open position the lock secures the blade open.
The knife utilizes a torsion spring around the pivot shaft that connects the blade to the handle and which is retained in a bushing. The spring drives the blade open in the automatic operational. One end of the spring rests against a wall of a pocket formed in the blade and extends through a slot in the bushing. The other end of the spring is fixed to the handle of the knife. When the blade is opened automatically, the spring and bushing rotate to drive the blade open; closing the blade rewinds the spring.
The knife includes a “dry fire safety” mechanism that prevents operation of the automatic opening mechanisms when the blade is in the open position or in any position intermediate between open and closed.